Device For Moving An Arrangement For Cutting And Welding Metal Strips

ABSTRACT

A device for moving at least one cutting and welding arrangement able to cut, then weld a tail of a first metal strip to a head of a second metal strip, includes at least one first carriage holding at least one welding head. The first carriage is movable over a guide path following a first course across a transverse strip region. At least one second carriage is movable separately from the first carriage and holds a cutting head. The second carriage is movable on a guide path following a second course. The welding head is used exclusively for a welding mode, the second carriage is used exclusively for a cutting mode and the two carriages have parked positions on either side of the tail and head widths of the strips. A welding method which is associated with the device is also provided.

The present invention relates to a device for moving an arrangement forcutting and welding a tail of a first metal strip to a head of a secondmetal strip, as well as a method associated with said device accordingto each of the preambles of claims 1 and 14.

In the domain of metallurgical processing of metal strips moving on aline comprising processing modules (mill, planer, furnaces, pickling,galvanizing, annealing, etc.), metal strips are ideally inserted fromcoils that are successively uncoiled in order to position samesequentially on said line. To achieve the continuous physical movementof the strips being processed, it is desirable to cut then weld a tailof a first uncoiled strip to a head of a second strip that has been atleast partially uncoiled, said strip tail and strip head being broughtto a welding installation, notably referred to as a welder, for thispurpose. During the welding operation, during which the strip tail andstrip head are necessarily immobilized by jaws for welding (aftercutting), it is necessary to at least limit or not to slow down thespeed of movement of the (welded) strip at the processes downstream ofthe welder. Furthermore, strip length accumulation means are installeddownstream and potentially upstream of the welder in order to enablecontinuation of the treatment process or processes despite the stoppingand/or slowing period at the welder on account of the accumulationand/or feed of the strip in the strip length accumulation means. Theseaccumulation means should be minimized as they are costly and bulky.Specifically, a processing line for such strips must tend to enable thecontinuous movement of the strips from an uncoiler at the line input toa recoiler or stack of cut strip sections at the line output. It istherefore desirable to minimize the duration of each strip stoppage (atleast of a tail and/or of a head) at a point of the line such as in thewelder while reducing accumulation that is not productive inasmuch as itrepresents only costs corresponding to a drop in productivity on theline caused by a reduction in the average speed of movement of the stripin the processing line and an increase in the equipment used to mitigatethe slowing of the strip in certain sections of the line, such as usingstrip accumulation means.

Furthermore, coil strips may have different metallurgical properties,thicknesses and widths when entering a welder, in particular ifdifferent types and formats are processed. There are currently two maintypes of welder, light and heavy welders, used to weld different widthsand thicknesses of metal strips in consideration of the stresses exertedon the welded zone by actions induced by the processes downstream of thewelder. In other words, for wider welding applications in each of the“light or heavy” domains, it is desirable to be able to extend thewelding ranges to greater strip formats and types, or even the contrary.However, in the case of a welder designed for small-format strips, if itis desired to extend welding to a larger format (assuming that thewidths, thicknesses and metallurgical characteristics of the strips donot exceed the capabilities of said welder), the welding time shall beincreased at least in proportion to the increase in weld length relatedto the desired width. This slows the productivity of the processing line(downstream) and potentially requires additional accumulation meansdownstream. In addition to the fact that the non-productive time has anegative impact, it is also necessary to provide increased capacitystorage accumulators designed for wider strip formats. Accordingly, itis evident that such downstream accumulation means (and upstreamaccumulation means, where applicable) will also necessarily be heavierand more costly than before for a welder to be adapted to weld largerstrip formats.

Primarily, the present invention is based on the prior art of a devicefor moving at least one cutting and welding arrangement able to cut thenweld a tail of a first metal strip to a head of a second metal strip,said device comprising at least a first carriage holding at least onewelding head, said first carriage being movable along a guide pathfollowing a first course across at least one transverse region (commonlyreferred to as the “width”) of the strip. Furthermore, the deviceincludes at least one second carriage movable separately from the firstcarriage holding a cutting head, said second carriage being movable on aguide path following a second course. Such a device is well illustratedand described in the publication DE102007023017A1 (see FIGS. 2a, 2b, 2c) showing such a two-carriage layout, the carriages each having headsthat can be switched between cutting and welding modes. This type ofswitchable head, primarily supplied by at least one laser source, iscurrently the flexible operating method technique best suited to cuttingand welding metal blanks of different shapes. However, these heads havethe drawback of not providing the same cutting and welding performancelevels as separate cutting and welding heads used exclusively forcutting or welding metal strips. This is all the more apparent since thestrips to be cut and welded may have different formats, thicknesses andmetallurgical, physical/mechanical characteristics and therefore presentstringent requirements in terms of cutting and welding performance,which are difficult to achieve using universal cutting and welding headtechnology. Furthermore, the device described in DE102007023017A1includes an intermediate step (FIG. 2b ), between a cutting step (FIG.2a ) and a welding step (FIG. 2c ), for adjusting at least one of thetwo carriages in relation to the other in order to move thelongitudinally aligned cutting heads to be switched to welding mode topositions transversely aligned in relation to an initial strip movementdirection. This intermediate step has two drawbacks: firstly, the timelost when changing the alignment of the heads and of the carriages,which necessarily reduces productivity or requires additionalaccumulation capacity, and secondly the high degree of alignmentprecision required for this dynamic carriage/head arrangement, whichrequires costly alignment means to achieve the required reliability androbustness. Such means for precisely aligning carriages and the heads ofsame advantageously enable the device according to DE102007023017A1 tobe easily used to weld segments of two metal sheets using free-formwelds, but the present invention relates to cutting and welding linearedges of strip tails and heads, i.e. simpler profiles.

Finally, the present invention is also intended to provide analternative to a conventional technique referred to as “single carriage”fitted with welding and cutting heads, for example in the arrangementcomprising a single carriage fitted with a pivoting arm with multipleswitchable cutting/welding heads, as set out in the same publicationDE102007023017A1(FIGS. 1a, 1b, 1c ) and in JP S60-257983. This type ofstructure also has drawbacks related to dual-function cutting andwelding heads and an intermediate step (such as in FIG. 1b inDE102007023017A1) that takes up too much time in terms of cycle andprecision, as described above.

It should also be noted that cutting and welding devices that requirealignment and/or pivoting means supported by one or more support andguide elements require such elements to be complex and therefore bulkyand/or heavy, all the more so since precision and reliability of suchmeans are required for installations working around the clock. Suchelements are most commonly large and C-shaped to enable the movement,beside the strip, of cutting, welding, burnishing, quality control andheating heads, etc., regardless of the presence of said strip.

Moreover, if other modules are required in addition to the deviceaccording to the invention, such as at least one of the followingmodules:

-   -   weld quality control means,    -   welded zone burnishing unit,    -   means for annealing a zone to be welded and/or a welded zone,        the device described above will be even larger and bulkier, and        it would be extremely complicated or even impossible to        incorporate such modules therein (for example burnishing means        on carriages pivoting or executing non-linear cutting/welding        profiles). Accordingly, known devices for moving at least one        cutting and welding arrangement clearly lack modularity.

One purpose of the present invention is to propose a device for movingat least one cutting and welding arrangement able to cut, then weld atail of a first metal strip to a head of a second metal strip, saiddevice addressing the known problems described in the prior art andabove.

In particular, the invention addresses problems with a view to proposingthe following advantages:

-   -   Reducing the means for accumulating the moving strip, increasing        productivity, shortening the duration of a cutting and welding        cycle,    -   Simplifying the cutting and welding cycle,    -   Using (separate) high-performance cutting and welding heads,    -   Enhancing adaptation to different strip formats and properties,    -   Improving the simplicity, modularity, integration and        streamlining/compacting of bearing/carriage structures,    -   Limiting the excessive mechanical structural tolerances        required, in particular using a dynamic precision aspect for the        movement and positioning of carriages and cutting/welding heads        on variable cutting and welding courses, which may vary between        tens of centimeters and several meters,    -   Reliability and robustness of the repetitive functions required        for welding the strips,    -   Facilitating machine maintenance operations in particular on        account of easy access to the different heads and modules.

In association with such a movement device, a method for cutting andthen welding is also proposed, said method being in particular optimizedin terms of the minimum stoppage time of strips in a welder, i.e.preventing the time lost outside a cutting step and a welding step ofthe strip tail and head, in particular using the movement device.

Such a movement device and a related welding method are thereforeproposed by means of the features in claims 1 and 14.

A set of sub-claims also sets out the advantages of the invention.

Primarily, on the basis of a device for moving at least one cutting andwelding arrangement able to cut then weld a tail of a first metal stripto a head of a second metal strip, the invention proposes a devicecomprising a first carriage holding at least one welding head, saidfirst carriage being movable along a guide path following a first courseacross one transverse region of the strip, determined as a function of acutting and welding width of said strip tail and head. The deviceincludes at least one second carriage movable separately from the firstcarriage holding a cutting head, said second carriage being movable on aguide path following a second course. Finally, the device according tothe invention is characterized in that:

-   -   the welding head is used exclusively for a welding mode for the        tail and head of cut strips,    -   the second carriage is used exclusively for a cutting mode, i.e.        it only includes at least one cutting unit, ideally formed by        two cutting heads respectively arranged on the tail and head        edges of the two strips.

In other words, the first carriage does not perform a cutting function,since it only carries at least one welding head (i.e. cannot be switchedto a cutting mode).

Since the first and second carriages are separately movable and haveseparate welding and cutting modes, the device according to theinvention provides an excellent degree of modularity, enabling same tomove successively and directly from a cutting mode to a welding mode. Nointermediate step for repositioning at least one of the two carriagesand/or the heads of same is required between the cutting and weldingsteps, unlike DE102007023017A1 (FIG. 1b ) and JP S60-257983 (by pivotingthe arm 15). It is therefore possible to advantageously limit themechanical structural tolerances required in particular by means of adynamic precision aspect for the movement and intrinsic positioning ofthe carriages and cutting/welding heads between the cutting and weldingsteps. Very precise mechanical structural tolerances are only requiredon the variable cutting and welding courses. Furthermore, the complex,bulky and costly means for intermediate translational or pivotingmovement between said cutting and welding modes are thus eliminated. Thedevice according to the invention is therefore also significantlystreamlined and the supporting structure of same using a single guidepath (ideally simply longilinear) for the two carriages can be smallerand less bulky than the structures described in the prior art.

Given that an intermediate step between the cutting and welding steps isperformed by activations directly following movement of the twocarriages of the device according to the invention, the duration of acutting and welding cycle is minimized, which advantageously reduces theneed for moving-strip accumulation means and increases productivity.

Preferably, in the device according to the invention, the two guidepaths of the first and of the second carriages are at least parallel oridentical if the positioning of the cutting or welding head on each ofthe carriages is predetermined before movement of the carriages isactivated. Furthermore, simple lightweight means for finely adjustingthe position of the welding head on the first carriage can be added tothe first carriage.

According to one embodiment, preferred for its simplicity, in the deviceaccording to the invention, the second carriage has at least two cuttingheads, ideally with a fixed gap in order to simultaneously andtransversely cut the heads and tails of two strips to be butt-weldedwith a constant distance between two transverse cutting planes. Saiddistance is determined by a gap value (Ec) that is in particulardependent on the dimensions (which are known and therefore predefinable)of the clamping jaws and of the chassis of the first carriage and thededicated head thereof.

Ideally, the guide parts of the first and of the second carriages haveat least one simple longilinear guide parallel to the cutting planes ofthe strips to be cut and welded. The length of said guide is at leastthe sum of the length of the course of the cutting carriage and theusable length in parked position of the two carriages on either side ofthe largest-format strip tail and head. This guide may be provided indifferent ways, using at least one slide, at least one rail, or anyother linear guide means for the carriages facing at least one of thecommon faces of the tail and head of the strips to be welded. The highlysimplified structure of same keeps it smaller and less bulky than theguide devices known in the prior art, such as C-shaped supports or anyother support strengthened to carry nested shifters/pivots.

Other advantages and embodiments of the device according to theinvention, as well as an associated method, are advantageously possibleand provided using the figures described:

FIG. 1 Movement device according to the invention in pre-cuttingposition,

FIG. 2 Movement device according to the invention in the positioncorresponding to the end of the cutting step and in pre-weldingposition,

FIG. 3 Movement device according to the invention provided with meansfor precisely/finely adjusting the position of the welding head,

FIG. 4 Movement device according to the invention in the positioncorresponding to the end of the welding step,

FIG. 5 Movement device according to the invention in pre-cuttingposition, viewed from the front in relation to a strip movementdirection.

FIG. 1 is a top view of a set of metal strips (B1, B2, B1′, B2′) ofdifferent widths moving in a longitudinal direction (Def) (=directioninverse to the axis Ox) through a welder. Only two welder jaws (M1, M2)are shown for the sake of clarity in order to simply represent saidwelder, said jaws being used to block, in a clamped position,respectively that strip tail (B1, B1′) and the strip head (B2, B2′) andthen to move the strip head (B2, B2′) towards the strip tail (B1, B1′).The welder includes a device for moving at least one cutting and weldingarrangement according to the invention. FIG. 1 shows said device inpre-cutting position.

Primarily, said device for moving at least one cutting and weldingarrangement is able to cut, then weld a tail of a first metal strip (B1)to a head of a second metal strip (B2).

The device includes a first carriage (Ch1) holding at least one weldinghead (S1), said first carriage (Ch1) being movable over a guide path(Cg1) following a first course (C1) across a transverse strip region.The length of the first course (C1) enables efficient welding on atleast the shortest of the widths of the cut-strip tail and head. Thedevice includes at least one second carriage (Ch2) movable separatelyfrom the first carriage holding a cutting head (D1), said secondcarriage (Ch2) being movable on a guide path (Cg2) following a secondcourse (C2). The length of the second course (C2) enables efficientcutting on at least the largest of the widths of the tail and head ofthe strips to be cut.

Finally, the device according to the invention is characterized in that:

-   -   the welding head (S1) is used exclusively for a welding mode,    -   the second carriage (Ch2) is used exclusively for a cutting        mode.

In the top view of the welder in FIG. 1, the two carriages are arrangedon one side of the strip tail and head (B1, B2), i.e. in parked positionbefore commencement of a cutting step using the second carriage (Ch2).The two guide paths (Cg1, Cg2) are at least parallel or identical,thereby inter alia making the device very simple, since all of thecutting and welding steps can firstly be carried out directly andsuccessively. Secondly, the movement of the carriages caused by saiddevice is exclusively and simply linear along the guide paths (Cg1,Cg2), the guide paths having at least one longilinear guide acting asbearing means.

Advantageously, in the device according to the invention, the secondcarriage (Ch2) has at least two cutting heads (D1, D2), ideally with afixed gap (Ec) in order to simultaneously and transversely cut the headsand tails of two strips to be butt-welded with a constant distancebetween two transverse cutting planes (Pc1, Pc2). This distance iseasily determined by a gap value (Ec) that is in particular dependent onthe dimensions of the clamping jaws (opened in cutting position) and ofthe chassis of said carriage.

The first carriage (Ch1) has a least one of the following modules (M):

-   -   weld quality control means,    -   welded zone burnishing unit,    -   means for annealing a zone to be welded and/or a welded zone.

In particular, the burnishing unit including a weld compression rolleris also very easy to build into the first carriage, since the roller isarranged in an exclusively transverse plane (Oy, Oz) like the weldinghead (S1) and does not encroach on the limited space between the jaws,in particular when the clamping jaws are closed during the welding step.The same is true for integration on the first welding carriage of meansfor checking weld quality and/or means for annealing a zone to be weldedand/or a welded zone (i.e. arranged upstream and/or downstream of thewelding head).

FIG. 2 shows the movement device according to the invention and FIG. 1,but in the position corresponding to the end of the cutting step and inthe pre-welding position, i.e. at the end of the cutting step describedin FIG. 1, once the second carriage (Ch2) has been moved in cutting modefor the strip tail and head (B1, B2) on the second course (C2). Thefirst welding carriage (Ch1) is therefore still positioned in theinitial parked zone on one side of the strips (B1, B2) and the secondcarriage (Ch2) is in the parked zone position on the other side of thestrips (B1, B2). At this stage, at least one of the welder jaws (M2)clamped on the strip (B2) is moved towards the other jaw (M1) in theaxial direction (Ox, Mid) in order to arrange the tail and head of thestrips (making the cutting planes (Pc1, Pc2) match perfectly) oppositeone another about a welding plane (Ps1), which in FIG. 2 is the same asthe cutting plane (Pc1).

It is nonetheless possible, depending on the format, that the thickness,the physical properties of the strips to be welded, the welding method,and the cut tail and head edges of the strips may have more or lesssignificant play, thereby requiring the welding plane to besubstantially offset and adjusted axially (=longitudinally in thedirection (Ox) in the direction of movement (Def) of the strips) fromthe initial completed cutting plane (Pc1) of the strip tail (B1). Forthis purpose, precise/fine adjustment means are proposed in FIG. 3, inwhich at least the welding head (S1) of the first carriage (Ch1) isinstalled on a mobile unit (UM) enabling an axial adjustment (Ra) of theposition of said head (S1) in relation to the cutting and welding axes(Pc1, Ps1). More specifically and very simply, the mobile unit (UM) isarranged on a guide path rigidly connected to the first carriage (S1) asa linear guide path (Cg_lin) with an angle (α) in relation to thecutting and welding axes (Pc1, Ps1) of for example ˜1°<α<90°. Thus, forexample, if the angle chosen is approximately 10°, a lineartranslational movement of 10 mm along the linear guide path (Ch_lin)will enable a finer actual axial offset of approximately 1 mm in thedirection (Ox, Mid). As such, the linear translational movement does notrequire high-precision movement means (which are costly and possiblylarger and heavier) since the precision required for “finer” axialadjustment is simply increased by reducing the angle (α) if required.The linear translational movement along the linear guide path (Ch_lin)and/or a change of angle may be implemented manually or automaticallyusing small, low-precision mechanisms depending on the types and formatsof the strips being welded.

FIG. 4 shows the movement device according to the invention in theposition corresponding to the end of the welding step along the firstwelding course (C1), the first and second carriages (Ch1, Ch2) being inparked zone position on the opposite side of the strips (B1, B2)initially defined in FIG. 1. The cutting and welding steps are thenperformed without an intermediate step for repositioning the carriagesor heads.

FIG. 5 shows the movement device according to the invention inpre-cutting position (see FIG. 1), viewed from the front (plane Oy, Oz)in relation to a strip movement direction (Ox). The device according tothe invention has a third carriage (Ch3), moveable separately from thefirst and second carriages (Ch1, Ch2) and moveable on a guide path (Cg3)following a course (C3) at least parallel to the guide paths (Cg1, Cg2)and including at least one of the following modules (M):

-   -   optionally at least one welding head,    -   weld quality control means,    -   a welded-zone burnishing unit,    -   means for annealing a zone to be welded and/or a welded zone.

The first and third carriages (Ch1, Ch3) are arranged respectively oneach side of the strip tail and head faces, and in particular each ofsaid carriages is separately moveable on two parallel and separate guidepaths (Cg1, Cg3). The courses of the first and third carriages (Ch1,Ch3) are parallel and the movement of same is at least synchronous inspace and time during the welding, burnishing, quality control andannealing steps, in particular to enable burnishing of the upper andlower faces of a weld joint being effected on a given zone duringmovement of the two carriages to guarantee perfect bilateral pointcompression. To carry the third carriage (Ch3), a single longilinearguide comparable to the one provided for the first and second carriages(Ch1, Ch2) can be arranged beneath the clamping jaws, in this case inthe lower part of the welder, if the longilinear guide of the first andsecond carriages (Ch1, Ch2) is arranged in the upper part of the welderin relation to the faces of the strips (B1, B2).

In general and for all of the examples shown in FIGS. 1 to 5, in thedevice according to the invention, the welding and/or cutting heads havea laser output suitable for welding metal strips, said output being inparticular coupled to a fiber-optic or air waveguide enabling a couplingof the guide to the laser output in synchronous movement with at leastone of the carriages related to one of said heads. In other words, thewelding and/or cutting heads are coupled at the input of same to atleast one laser source via demultiplication of the fiber-optic or airwaveguides. This embodiment enables the laser sources to be positionedremotely from said device according to the invention so as not tooverload the carriages and therefore to avoid the carriage-bearing andlongilinear-guide means from becoming too large and too heavy.

Alternatively, the cutting heads can use a mechanical method, usingplasma or a high-pressure fluid jet, to implement a cutting stage of thestrip tail and head (B1, B2). In this case, as with laser cutting, thecarriages only have to carry a minimum number of cutting elements, sinceall energy or mechanical feed modules for the cutting head are remotelypositioned away from the second cutting carriage. Thus, the size andweight of the second cutting carriage is kept to a minimum, therebyadvantageously reducing the size and weight of the device according tothe invention.

Furthermore, in the device according to the invention, the firstcarriage (Ch1) holding at least the first welding head (S1) can alsohold at least one additional welding head in at least one intermediateposition in the transverse welding direction (Oy) on the first carriagethat, when said carriage is moved such that the welding head (S1) on theend of the supporting element is opposite one of the faces of the strips(B1, B2) such as for example above the strips (B1, B2) at a distance ofat least one half-width of the strips, the additional head is positionedon the edge of the variable width of the strip, i.e. the edge of thestrip having the shortest width. As such, the welding width is segmentedinto at least two half-widths, which halves the duration of the originalwelding cycle using one welding head. It is also possible to add two,three, etc. additional welding heads to increase weld joint segmentationacross the width of the strips to be welded. One or more additionalwelding head adjustment support units are then installed on the firstcarriage (Ch1) in order to carry and move said additional welding heads.The intermediate position of the additional welding head or heads on thefirst welding carriage can also be adjusted in the transverse direction(Oy) and as a function of the variable width (L1, L1′; L2, L2′) of atleast the strip having the shortest width, the position being adjustedin particular manually or autonomously, and ideally motorized. Thus, atleast one additional welding head is installed on the first weldingcarriage (Ch1) by means of an adjustment support unit, said adjustmentunit enabling a transverse positioning course of at least the additionalwelding head.

This advantageously reduces the duration of a welding step by a factorof at least two and potentially more if the number of additional headsis greater than two. Finally, each of the courses required to performthe welding (using fixed and additional heads) on the products to bewelded are equally reduced by a factor of two or more, which enableshigh-precision guidance on a limited course with low mechanicalstructural tolerances, which advantageously minimizes implementationcosts. This enables simplification of a head holding support design,i.e. avoiding any over dimensioning of said supporting element (and evenenabling the dimensions to be reduced), dispensing with designproperties of the supporting element used to ensure greater carryingaccuracy, in particular on longer courses.

Finally, the invention incorporating the embodiments related to themovement device presented proposes a cutting and welding method able toweld a tail of a first metal strip to a head of a second metal strip,the two strips moving (Def) continuously on a metal processing line, inwhich the first and second strips are inserted into a welder includingthe movement device according to the invention and at least two pairs ofclamping jaws for the tail and the head, and where at least the firstand second, and potentially the third, carriages (Ch1, Ch2, Ch3) areplaced in an intermediate parked position (=on either side of the stripwidths) or moved along a single physical guide path (Cg1, Cg2) or on twoguide paths (Cg1, Cg3) that are physically separate and parallel as afunction of the sequencing cycle of the cutting, welding and potentiallyquality control, burnishing and annealing operations on the weld zone.

Said method according to the invention advantageously provides for thecarriages (Ch1, Ch2, Ch3) to move as a function of the distance betweenthe pairs of jaws according to at least two gap values for each pair ofjaws (open for cutting and closed for welding). Inversely, theinstantaneous position of each of the cutting and welding carriages(parked, beside the strips) provides information to a module forcontrolling the position of the jaws in order to seamlessly concatenatethe cutting and welding steps.

By way of example for uncoiled metal strips having a width ofapproximately 2 m and a thickness of less than 10 mm, the welding methodaccording to the invention enables activation of a first simultaneouscutting phase for the tail of the first metal strip and the head of asecond metal strip for a first largest gap value (for example 450 mm)between each pair of jaws, carried out before a welding phase of thetail and head for a second smallest value (for example 6 mm) betweeneach pair of jaws. The movement of the jaws from 450 mm to 6 mm istriggered once the second cutting carriage leaves its cutting zone forthe parked position after cutting (FIG. 2).

1-15. (canceled)
 16. A device for moving at least one cutting andwelding configuration for cutting and then welding a tail of a firstmetal strip to a head of a second metal strip, the device comprising: atleast one first carriage being movable over a guide path following afirst course across a transverse strip region; at least one welding headbeing held by said at least one first carriage and being usedexclusively for a welding mode; at least one second carriage beingmovable separately from said at least one first carriage on a guide pathfollowing a second course, said at least one second carriage being usedexclusively for a cutting mode; and a cutting head being held by said atleast one second carriage; said at least one first carriage and said atleast one second carriage each having a parked position on eachrespective side of a width of the strip tail and the strip head.
 17. Thedevice according to claim 16, wherein said guide paths are parallel oridentical.
 18. The device according to claim 16, wherein said cuttinghead is one of at least two cutting heads being held by said at leastone second carriage.
 19. The device according to claim 18, wherein saidat least two cutting heads define a fixed gap therebetween in order tosimultaneously and transversely cut the heads and tails of two strips tobe butt-welded with a constant distance between two transverse cuttingplanes.
 20. The device according to claim 16, wherein said guide pathsinclude at least one longitudinal linear guide path.
 21. The deviceaccording to claim 19, which further comprises a mobile unit, said atleast one welding head being installed on said mobile unit enabling anaxial adjustment of a position of said at least one welding headrelative to said cutting and welding planes.
 22. The device according toclaim 21, wherein said mobile unit is disposed on a guide path rigidlyconnected to said at least one first carriage as a linear guide pathdisposed at an angle relative to said cutting and welding planes. 23.The device according to claim 22, wherein said angle (α) is ˜1°<α<90°.24. The device according to claim 16, wherein said at least one firstcarriage has at least one of the following modules: a weld qualitycontrol device, a welded zone burnishing unit, a device for annealing azone to be welded or a welded zone.
 25. The device according to claim16, which further comprises: a third carriage being moveable separatelyfrom said at least one first and said at least one second carriages,being moveable on a guide path following a course at least parallel tosaid guide paths and including at least one of the following modules: aweld quality control device, a welded zone burnishing unit, a device forannealing a zone to be welded or a welded zone.
 26. The device accordingto claim 16, which further comprises: at least one third welding headbeing held by said at least one first carriage in at least oneintermediate position, in addition to said at least one welding headbeing held on said at least one first carriage; and said at least onethird welding head being positioned on an edge of a variable width ofthe strip having the shortest width when said at least one firstcarriage is moved such that said at least one welding head on an end ofa supporting arm is opposite one of the faces of the strips at adistance of at least one half-width of the strips.
 27. The deviceaccording to claim 26, wherein said first and third carriages are eachdisposed on a respective side of strip tail and head faces.
 28. Thedevice according to claim 27, wherein each of said first and thirdcarriages is separately moveable on two parallel and separate guidepaths.
 29. The device according to claim 16, wherein at least one ofsaid welding or cutting heads has a laser output suitable for weldingmetal strips.
 30. The device according to claim 29, wherein said laseroutput is coupled to a fiber-optic or air waveguide enabling a couplingof at least one of said guide paths to said laser output in synchronousmovement with at least one of said carriages relative to one of saidheads.
 31. The device according to claim 29, wherein at least one ofsaid welding or cutting heads has an input coupled to at least one lasersource via demultiplication of said fiber-optic or air waveguides. 32.The device according to claim 16, wherein said cutting heads cutmechanically or by using plasma or a high-pressure fluid jet.
 33. Acutting and welding method for welding a tail of a first metal strip toa head of a second metal strip, the method comprising the followingsteps: continuously moving the first and second metal strips on a metalprocessing line and inserting the first and second metal strips into awelder including a movement device having: at least one first carriagebeing movable over a guide path following a first course across atransverse strip region; at least one welding head being held by the atleast one first carriage and being used exclusively for a welding mode;at least one second carriage being movable separately from the at leastone first carriage on a guide path following a second course, the atleast one second carriage being used exclusively for a cutting mode; anda cutting head being held by the at least one second carriage; the atleast one first carriage and the at least one second carriage eachhaving a parked position on each respective side of a width of the striptail and the strip head; clamping the tail and the head of the metalstrips in at least two pairs of clamping jaws; and placing the first andsecond carriages in an intermediate parked position or moving the firstand second carriages along a single guide path as a function of asequencing cycle of cutting and welding or cutting, welding and qualitycontrol, burnishing and annealing operations on a weld zone.
 34. Themethod according to claim 33, which further comprises providing a thirdcarriage, and placing the first, second and third carriages in theintermediate parked position or moving the first, second and thirdcarriages along two guide paths being separate and parallel as afunction of the sequencing cycle.
 35. The method according to claim 33,which further comprises moving the carriages as a function of a distancebetween the pairs of jaws according to at least two gap values for eachpair of jaws being open for cutting and closed for welding.
 36. Themethod according to claim 34, which further comprises moving thecarriages as a function of a distance between the pairs of jawsaccording to at least two gap values for each pair of jaws being openfor cutting and closed for welding.